如何将数据插入到其他列中没有 NULL 的特定列中？

Question

I have a table ("table1") with 3 columns called col1, col2 and col3 (each is VARCHAR) with 4 values as shown below:

col1   col2   col3
datA1  datB1  datC1
datA2  

I need an ability to add a data at any time into any column NOT affecting on the other ones. The very popular code in the Internet is that (say, we need to add data only to the columns col2 and col3):

INSERT INTO table1 (col2, col3)
VALUES ('datB2', 'datC2');

But it adds new rows, like below:

col1   col2   col3
datA1  datB1  datC1
datA2
NULL   datB2  datC2

What I really need is to fill the row starting with value "datA2" at the column "col1" with new values and get the table like below:

col1   col2   col3
datA1  datB1  datC1
datA2  datB2  datC2

The table has 3 columns and each column responses for a particular type of values (say: name, colour, size). What I need is just a possibility to add new values at any time in a particular column and have them without Null and new rows if it has a free cell before.

Answer 1

UPDATE table1
SET col2 = dataB2, col3 = dataC2
WHERE col1 = dataA2;

This may serve your purpose.

Answer 2

You will have to use the UPDATE statement if you want to add data to an existing row. Like this for example:

UPDATE table1 SET
col2 = 'data5'
col3 = 'data6'
FROM table1
WHERE col1 = 'data4'

Also it does look like the root of your problem is poor database design, but this query is just to show you how to add data to an existing row.

Answer 3

I found the solution (a chain of logical operations):

1) CHECK if there is a cell (in the target column) with values either "" or NULL .

2) IF it has one of those then rewrite the FIRST one keeping the values of the other cells in this row at their places (assumably we use UPDATE ))) ).

3) ELSE just add a new row with all NULL s in the other cell in the row.

If we want to add a few values into various columns simultaneously we may prepare our queries for all of those and then execute them simultaneously (sorry for tautology).

If we need to add a few values into the same column within one query we can prepare it, using loops (repeating paragraphs 1 and 2 (or, optionally, 3).

Answer 4

Given a table structure, with two data rows:

key         value
--------------------
team        accounts
manager     jeff

Each time you want to change a value, you need to check whether it is already there (for update), or not (for insert). So, to change the value of the manager property:

if exists(select * from keyValues where key = 'manager')
    update keyValues set value = 'mike' where key = 'manager'
else
    insert into keyValues ('manager', 'mike')

Answer 5

Suppose you have the table
CLIENT_MASTER

ClientNo Name
C00001 Ivan
C00002 Himanshu

Now you add a new column City

ALTER table CLIENT_MASTER  
ADD( City varchar(10));

Now if you want to add values in already existing rows you can use UPDATE command.
For example

UPDATE CLIENT_MASTER  
SET City='Delhi'  
WHERE ClientNo='C00001';

The updated table is
ClientNo Name City
C00001 Ivan Delhi
C00002 Himanshu NULL

Answer 6

Use this:

INSERT INTO table1 (col2, col3)
VALUES ('datB2', 'datC2')
WHERE col1 = datA2;

Answer 7

Use this, if value null then insert empty value.

$cal1=$cal1 ? "data5" : '';
$cal2=$cal2 ? "data6" : '';
INSERT INTO table1 (col2, col3)
VALUES ("'.$cal1.'", "'.$cal2.'");